Conventionally, a magnetic sensor for monitoring the magnetic moment of a magnetic thin film can be implemented using the Hall effect, the magnetoresistance effect, an induction coil, a superconducting quantum interference device (SQUID), etc. A method for measuring a magnetic field using the magnetic sensor is used as the monitoring method.
First, a method using the Hall effect uses a phenomenon in which electromotive force is generated as an electric field is generated in a direction perpendicular to an electric current direction and a magnetic field direction when the magnetic field is applied to a plate into which current flows.
Next, a method using the magnetoresistance effect uses a phenomenon in which electric resistance varies in proportion to the square of the strength of a magnetic field. Moreover, this method measures the magnetic field by sensing the effect of the magnetic field to an induction coil according to Faraday's law of electromagnetic induction.
A method using the SQUID can measure the magnitude of a magnetic field up to 10−10 Gauss using flux quantization and the Josephson effect present in a superconducting state.
A vibrating sample magnetometer (VSM) uses Faraday's law of electromagnetic induction associated with an electric field generating a magnetic field varying with time, measures the electric field, and informs a user of information about the varied magnetic field. The VSM is used for measuring magnetic properties associated with a magnetic material serving as a sample.
An alternating gradient field (AGM) is used for extracting periodic force applied to a sample positioned within a varying or direct current (DC) field. The periodic force is proportional to the magnitude of a magnetic field applied to the sample and a magnetic moment of the sample.
The periodic force finely moves the sample. This motion is measured by a sensing part using a piezoelectric material mounted on an arm of a probe. Furthermore, a value of the measured motion is used for producing a value of the magnetic moment and a hysteresis curve associated with the sample.
When polarized light is incident into a magnetic sample and an interaction between the incident light and the magnetic moment within the sample changes a polarization degree, magneto-optical Kerr effect (MOKE) is used for measuring magnetic properties of the sample by measuring a change of the polarization degree.
A magnetic material deposited on a cantilever receives a force caused by an external torque field, and the force finely moves the cantilever. At this point, capacitance varies between the cantilever and an electrically conductive plate formed on a lower part of the cantilever. A capacitance detection cantilever chip magnetometer analyzes properties of a magnetic film deposited on the cantilever using the varied capacitance.
However, the conventional system can monitor the magnetic moments of thin films only after the thin film has been deposited, such that there is a problem in that it cannot monitor the magnetic moment of the thin film during the film deposition.
Furthermore, the conventional monitoring system must perform measurement after the thin film has been deposited and a vacuum has been broken, such that there is a problem in that the thin film is oxidized and a measurement result can be produced only after the thin film has been deposited.
Part of the conventional monitoring system can perform measurement without breaking the vacuum state, but there is still a problem in that a measurement result can be produced only after the thin film has been deposited.
Furthermore, the conventional monitoring system can measure properties of a magnetic film with several Angstrom precision, but cannot measure properties of a magnetic film with sub-angstrom precision, such that there is a drawback in that magnetic properties acquired from a process for depositing a ultra-thin film cannot be examined.